Does too much T.V. change our cognitive abilities for the worse? Possibly, according to researchers from Univerity College London, who found that adults who watch more than three and a half hours of T.V. daily more than doubles memory decline in adults over 50.
Considering that U.S. adults watch an average of six-plus hours of video per day, that’s a scary number. Here’s how scientists came up with it: They followed over 3,600 people over the age of 50 for six years. They asked the participants how much T.V. they watched at the begining of the study starting in 2008, and then again when it ended in 2014 and 2015. Alongside their questions about T.V. watching, scientists gave the participants verbal memory tests at the beginning and end of the study.
People who watched three and half or more hours of T.V. per day declined an average of eight to ten percent. Those who watched less, comparatively, declined between four and five percent.
What does this mean in an era of streaming television, when entire seasons of T.V. shows are released at once and there’s no shame in admitting you spent all 48 hours of your weekend binging your favorite show? Do television shows really rot your brain, like your parents told you as a child?
“Our findings have led to several other research questions,” said Dr. Daisy Fancourt, co-author of the study. “For example, do different types of television content have different effects on cognitive decline? Given the associations with cognitive decline shown here, is television viewing specifically a risk factor for the onset of dementia?”
Those are questions that the researchers can’t answer yet. Although television has long been documented to affect cognition, most studies are geared toward its effect on the brain during childhood development.
“There has been interest for over a decade in the effect of television viewing behaviors on cognition, but much of this literature has concentrated on children,” said Dr. Daisy Fancourt, lead author of the study. “Much less attention has been paid to the effects of television viewing at the other end of the lifespan, despite it being hypothesised for over 25 years that watching excessive television could contribute to the development of dementia.”
In children, studies show that while some T.V. shows may improve language acquisition and visual motor skills in very young children, “many more studies have shown concerning cognitive associations including with poorer reading recognition, reading comprehension and maths, and cognitive, language and motor developmental delays,” wrote the auhors in the published study, which appeared in the journal Scientific Reports.
Some might point to T.V.-watching being detrimental because it replaces healthier activities like exercising that are proven to keep our brains sharp. But it isn’t just the sedentary nature of glazing over in front of the T.V. that is cause for concern, said the researchers.
“Associations between television viewing and verbal memory remained even when considering a range of variables relating to sedentary behaviors, suggesting that it is not just the sedentary nature of television watching that is responsible for its relationship with cognition,” they wrote.
It could be that extra time with the telly translates to less time sleeping—a necessary activity to help clear plaques of protein from your brain. A build-up of too much plaque and too little sleep has also been shown to contribute to cognitive decline.
But regardless of why this association exists, it doesn’t prove that television causes dementia.
“While this study looks at a large number of people and accounts for long-term illnesses and exercise levels, it’s important to remember that cognitive decline is not the same as dementia,” said Chris Allen, a senior cardiac nurse at the British Heart Foundation, which part-funded the study.
“We all like to curl up in front of the TV and watch our favorite shows. But if you’re concerned that the amount of television you’re watching could be having a negative impact on your health, we would advise limiting the amount of TV you watch each day and working in some heart-healthy hobbies to your routine.”
Instead of turning on the television every night, scientists recommend activities that stimulate your brain, like reading or playing board games.
“Whilst watching television may also have benefits such as educational benefits from watching documentaries and relaxation benefits as a way of reducing stress, overall this suggests that adults over the age of 50 should try and ensure television viewing is balanced with other contrasting activities,” said Fancourt.